In recent years, an increasing number of manufacturers of popular small pickup trucks and similar vehicles have mounted the spare tire vertically on the back of the vehicle. The spare is mounted on three or more studs that project from the back of the vehicle, and is fastened in place with stud nuts.
To prevent theft of the spare tire, various means are used, the most prevalent being replacement of one of the stud nuts with a special locking nut. This special locking nut requires a key to operate it and is usually effective in preventing unauthorized removal of the spare. However, someone using a heavy wrench or cutters may succeed in twisting off the locking nut to remove the spare tire. To augment the special locking nut, some owners add chains and a padlock to hold the spare tire firm to its mounting. These can be defeated by a determined thief armed with heavy cutters. Thus, there is a need for a locking device that can not be easily tampered with or defeated.